Glad a few folk got on here - I had a real close look at the pasture that cow is in - now I own Herfs and I know they will eat almost anything - but the fact is if the grass is cut down to the dirt and there is a lot of tall green stuff standing - that is a starvation pasture - they will only eat what is left standing to stay alive. Try to keep the animals off of it in the future and do some work to bring it back.
A herf - shorthorn (milker or not) will get to be a real nice solid animal - we are crossing about 8 to shorthorn at home this summer - hopefully I get to see those calves before they go to market
Now - when you go to feeding this animal hay - here is a suggestion that you might not like but it will become readily apparent to you how much food this animal requires when you do it.
You throw hay out there in measured amounts until she can't eat any more. That is what she needs today. Tomorrow she will want a little more and the day after she will want a little more.
I bet you she eats at least one full 50 pound square bale a day to start off - and there will be little to no waste as she will eat for 16 hours straight. You can work her up to this if you want - I never bother when I take in an animal in this condition - she will regulate herself good enough because she is not stumbling hungry - yet. If you feed her alfalfa she will schitte through the eye of a needle (protein too high for her system) though, so take her up on grass first
You can go with corn as well if you want - personally I never bother - but I do know it works real well - so choice is yours.
I think you will be real surprized at the amount of hay she goes through at the start - and what she needs to maintain her weight.
In fact I bet you start to beach at the cost of her feed - but that is because she is so run down.
Here is a tip for you on pasture.
Good solid pasture will yield about 300 pounds of grass per inch per acre. If it is a healthy pasture it will do this for a long time and if you take the cows off of it before it gets under 6 inches in height it will come back a lot faster than if you let them eat it down to the ground.
I figure your pasture - weeds put into play - yields less than 35 pounds of
grass per acre and it has virtually no recovery capability because the cow is close penned and cannot leave to eat elsewhere.
Get on to the weeds and get some grass seed and fert on it.
Gonna' cost you some bucks - but what you got her on is no where near enough. Our cattle on pasture - no grain - will wean a calf and never be less than the Herf you will see on the web page you went to - scoring 5-6 - we never let them get lower.
They will come out of the winter - on straight hay and living outside in the rain and the snow with only a cedar bush on a hillside for shelter with a score of 6-7 and sometimes better - and sometimes even a bit more than we like for calving - but they do well. But they get all the hay they can stand - the ground is never empty in front of them - never - and that is the difference between you and us. Yours is hungry all the time.
If you have a cow that weighs 1000 pounds and she is doing nothing she needs about 30 pounds of grass to keep her where she is. If she is milking hard and only on grass it can come close to double that. You now know how poor your pasture is and you need to fix it.
Cheap way to go - spray the weeds out with 24D if legal in your world. Put down a suitable pasture mix and about 1-200 pounds of a good quality fertilizer per acre - and stand back. Do this two years in a row - many will say it is over kill and I would agree with them - but it is such a small piece of ground the cost is nothing (to those that know the cost!! )
in the grand scheme of things - and it will literally boom. Mow it / clip it / keep it cut with no animals on it for a year.
That ground is tired and needs help - if you are unsure call your county ag folks or a local seed and fert place that you or someone you know trusts. Do not blink and do not gasp when you hear how much it might be to get it into shape - not cheap to many who have never done it - but it improves the overall worth of your property - and it is far from suitable for animals as it stands at this time.
Good luck
Bez+